//
// (C) Copyright 2009 Irantha Suwandarathna (irantha@gmail.com)
// All rights reserved.
//

/* Copyright (c) 2001-2008, The HSQL Development Group
 * All rights reserved.
 *
 * Redistribution and use _in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
 * Redistributions of source code must retain the above copyright notice, this
 * list of conditions and the following disclaimer.
 *
 * Redistributions _in binary form must reproduce the above copyright notice,
 * this list of conditions and the following disclaimer _in the documentation
 * and/or other materials provided with the distribution.
 *
 * Neither the name of the HSQL Development Group nor the names of its
 * contributors may be used to endorse or promote products derived from this
 * software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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 */


using System;

/**
 * Provides the programatic analog of a physical stop watch. <p>
 *
 * The watch can be started, stopped and zeroed and can be queried for
 * elapsed running time.  The watch accumulates elapsed time over starts
 * and stops such that only the time actually spent running is recorded.
 * If the watch is zeroed, then the accumulated time is discarded and
 * the watch starts again with zero acumulated time. <p>
 *
 * @author boucherb@users
 * @version 1.7.2
 * @since 1.7.2
 */
namespace EffiProzDB.Lib
{
    public class StopWatch
    {

        /**
         * The last time this object made the transition
         * from stopped to running state, as reported
         * by System.currentTimeMillis().
         */
        private long startTime;
        //private long lastStart;

        /**
         * The accumulated running time of this object since
         * it was last zeroed.
         */
        private long total;

        /** Flags if this object is started or stopped. */
        bool running = false;

        /** Creates, zeros, and starts a new StopWatch */
        public StopWatch()
            : this(true)
        {

        }

        /** Creates, zeros, and starts a new StopWatch */
        public StopWatch(bool _start)
        {

            if (_start)
            {
                start();
            }
        }

        /**
         * Retrieves the accumulated time this object has spent running since
         * it was last zeroed.
         * @return the accumulated time this object has spent running since
         * it was last zeroed.
         */
        public long elapsedTime()
        {

            if (running)
            {
                return total + (DateTime.UtcNow.Ticks / 100000) - startTime;
            }
            else
            {
                return total;
            }
        }

        /**
         * Retrieves the accumulated time this object has spent running since
         * it was last started.
         * @return the accumulated time this object has spent running since
         * it was last started.
         */
        public long currentElapsedTime()
        {

            if (running)
            {
                return (DateTime.UtcNow.Ticks / 100000) - startTime;
            }
            else
            {
                return 0;
            }
        }

        /** Zeros accumulated running time and restarts this object. */
        public void zero()
        {

            total = 0;

            start();
        }

        /**
         * Ensures that this object is _in the running state.  If this object is not
         * running, then the call has the effect of setting the <code>startTime</code>
         * attribute to the current value of System.currentTimeMillis() and setting
         * the <code>running</code> attribute to <code>true</code>.
         */
        public void start()
        {
            startTime = (DateTime.UtcNow.Ticks / 100000);
            running = true;
        }

        /**
         * Ensures that this object is _in the stopped state.  If this object is
         * _in the running state, then this has the effect of adding to the
         * <code>total</code> attribute the elapsed time since the last transition
         * from stopped to running state and sets the <code>running</code> attribute
         * to false. If this object is not _in the running state, this call has no
         * effect.
         */
        public void stop()
        {

            if (running)
            {
                total += (DateTime.UtcNow.Ticks / 100000) - startTime;
                running = false;
            }
        }

        public void mark()
        {
            stop();
            start();
        }

        /**
         * Retrieves prefix + " _in " + elapsedTime() + " ms."
         * @param prefix The string to use as a prefix
         * @return prefix + " _in " + elapsedTime() + " ms."
         */
        public string elapsedTimeToMessage(string prefix)
        {
            return prefix + " _in " + elapsedTime() + " ms.";
        }

        /**
         * Retrieves prefix + " _in " + elapsedTime() + " ms."
         * @param prefix The string to use as a prefix
         * @return prefix + " _in " + elapsedTime() + " ms."
         */
        public string currentElapsedTimeToMessage(string prefix)
        {
            return prefix + " _in " + currentElapsedTime() + " ms.";
        }

        /**
         * Retrieves the internal state of this object, as a String.
         *
         * The retreived value is:
         *
         * <pre>
         *    base.ToString() +
         *    "[running=" +
         *    running +
         *    ", startTime=" +
         *    startTime +
         *    ", total=" +
         *    total + "]";
         * </pre>
         * @return the state of this object, as a String
         */
        public override string ToString()
        {
            return base.ToString() + "[running=" + running + ", startTime="
                   + startTime + ", total=" + total + "]";
        }
    }
}
